Portable electrical measuring instrument.



W. E. BEEDE. PORTABLE ELECTRICAL MEASURING msmulmm .A PPLIQATIOH FILED D110. 21, 1909.

Patented Aug. 9, 1 910,

Invehior;

IVL' inecs'sebw Wag i. M1

balance concentrically mounted each such WALTER E. BEEDE, or NEW YORK, N. Y.

s PATENT enrich.

, ASSIGNOR- TO AMERICAN EVER READY COMPANY, A CORPORATION OF NEW YURK.

PORTABLE ELECTRICAL MEASURING INSTRUMENT.

To all whom it may concern: I

Be it known that I, VALTER E. BEEDE, a. citizen of the United .States, residing-at the borough of Manhattan, cityof New York,

[in the county of New York and State of New York, have invented certain new and useful Improvements in Portable Electrical Measuring. Instruments,'of which the fol lowing is a specification, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates to. portable electrical measuring instruments, such as are adapted to be carried in the pocket and which in general appearance resemble a watch.

The principal objects of my invention are compactness, simplicity and economy of construction, durability, reliability, and accuracy and sensitiveness of operation. My invention lncludes certain combinationsof parts adapted to accomplish these ob ects.

In carrying out my invent-ion, I provide a straight flattened solenoid'coil and a. flat,

tapered and curved armature core adaptedto pass through the solenoid coil, an arbor being provided for the armature core, and such arbor carrying also apointer and acounterbalance.

My invention also includes three members, to wit, a pointer, an armature and a countermember' being rotatlvely unbalanced and each being relatively rotatively adjustable to secure a common rotative balance.

My invention also includes, in combination, a base plate provided with an annulus forming a shallow cup, the base plate also being provided with struck-up portions.

- respectively forming a terminal for the solenoid coil, a bearing for the arbor and an anchor for a solenoid-opposing spring con nected to the arbor.

I shall now describe my invention with reference to thedrawings and shall there Specification of 'Letters Patent.

Application filed December 21, 1909.

' Patented Aug. a. rate.

Serial No. 534,256.

is a front View of the instrument. 4 .is a. detail view of. the rotatable arbor. and its. adjuncts as seen in Fig. 2;

In. the illustrated embodiment of the.invention, the working parts of the'dev'lce are shown as inclosed in a circular flattened casing of the watch case type, comprising a base plate 1 provided with an annulus2 'forming with the base plate 1 a shallow cup. The casing includes a rear cover Band a front-cover 4, the latter being provided with a transparent crystal 5. straight, flattened solenoid coil (3 is located substantially centrally of thecusing with one of its flattened sides adjacent to the rear cover 3 and theother of its flattened sides adjacent to the base plate 1, to'which the solenoid coil is-secured by: a sheet metal strap 7 passing through the coil and attached at its ends to the base plate 1 by screw-headed bolts 8 and nuts 9. A standard 10,'forming a terminal connection for one-of the terminals of the solenoid coil, is struck up from the base plate 1, leaving an opening 11 in the base plate, the terminal of the coil.-'6 being soldered to the standard 10. The othcnterminalyof the, coil 6 soldered to a curved metal strip'12 connected to a contact terminal 13 passing to the outside of the casing tl'n'ough an insulating, ring 14 seated in an opening in the annulus 2. Any partfof the casing may be employed as the'other contact terminal in using the device, but usually a separate and attached contact terminal is employed ha\-' i1i g a short flexible wire terminating in a plug adapted toloeZinserted in asocket 15 in the stem 16., The solenoid coil Groacts with a pivoted sheet metal arnmturc core 17 mounted. on a rotatable arbor .18. The arbor 18 is located in an eccentric relation to the casing and at one side of the solenoid coil substantially equidistant from the ends of such coil, as clearly shown in Fig. 1. The armature core 17 has, as shown in Fig. 1, a portion extending outward from the arbor and merging nto a tapered curved portion concentr c with the arbor l8 and entering the solenoid 1 parts carried thereby, including the arma terbalance 19, a spring drum 20, a pointer\ 21, and two end disks 22. In the illustrated i embodiment of the invention the end disks i .or retaining disks 22, the pointer 21 and! the spring drum 20 are fixed on or mounted to rotate with the arbor 18, while the armature core 17 and the counterbalance 19 are t'rictionally held by a strong frictional resistance between the spring drum 20 and one of the end disks 22. This construction permits of an accurate adjustment and correct balancing of the movable parts of the device.

The arbor 18 is provided with cone-shaped ends and has a bearing at one end in the base plate 1 and at theother end in a bearing arm 23, cut and struck up from the base plate 1, leaving therein an opening 24, and extending first outward from and then substantially parallel to the base plate, as shown in Figs. 1 and 2. A volute ribbon spring 25 is secured at its inner end to the spring drum 20 and at its outer end is soldered to an anchor post 26 struclr up from the base plate 1, leaving an opening 27. The spring 25 is adapted to rotate the arbor 18 and the cure core 17, in opposition to the solenoid coil 6, and causes the armature core 17, when not attracted by the solenoid coil, to abut against the annulus 2 of the casing which is in its path, as shown in Fig. 1.

The instrument has a dial 28 secured -to the front side of the base plate 1 by the bolts 8; and the dial is provided with a suitably calibrated direct reading scale 29, over which the pointer 21 is adapted to move. The pointer 21 is bent, as best shown in Fig.4, so as to pass through the hole 21 in the base plate and through a smaller arcuate slot 80 in the dial 28.

"When the coils of the solenoid coil 6 are energized by the passing of a current, the tapered armature core 17 will be drawn through the solenoid coil from the narrow and toward the wider portion of the armature core in opposition to the opposing rotational etlect of the spring 25. and the. pointer 21 will be moved to the indication on the scale 29 corresponding to the magnitude of the electrical energy being measured.

In its illustrated embodiment, the instrument is shown as adapted for use as an ammetcr. but the principles of the invention could as well be embodied in a slightly modified instrument adapted to be used as aj voltmeter. or in an instrument adapted for I use as both an ammeter and a voltmeter, that is to say, a volt-ammeter.

It is obvious that various modifications may be made in the construction shown and above particularly described within the principle and scope of my invention.

I claim:

1. In an electrical measuring instrument, the combination of an arbor, three members mounted thereon, to wit,-a pointer, an armature and a counter-balance weight, each such member being rotatively unbalanced in reference to the axis of the arbor and each such member being rotatively adjustable in reference to each of the other members about the axis of the arbor, a conductive coil controlling the armatur and means opposing the attractive action of the conductive coil on the armature.

2. A portable electrical measuring instru-' vment comprlsing a casing of the watch-case type, a straight flattened solenoid coil arranged with its flattened sides turned toward the flattened sides of the casing, an arbor located in an eccentric relation to the casing and at one side of the solenoid coil and substantially equidistant from the ends of such coil, a sheet metal armature core mounted on the arbor and having .a portion extending outward from the arbor and a I tapered curved portion concentric with the arbor and actuated by the solenoid. a pointer carried by the arbor, a scale for the pointer,

a spring surrounding the arbor and ar ranged-to oppose the solenoid coil. and a rotatively adj ustable counterbalance mounted 011 the arbor. 1

3. A portable electrical measuring instrument comprising a flattened casing of circular contour, a straight flattened solenoid coil arranged with its flattened sides adjacent to the flattened sides of the casin a pivoted sheet metal armature core having a portion extending outward from the pivot and a tapered curved portion concentric with the pivot and adapted to pass through the solenoid coil, an arbor forming a pivot for the armature core located in an eccentric relation to the casing and at one side of the solenoid coil and substantially equidistant from its ends, a pointer carried by the arbor, a scale for the pointer, a counterbalance for the pointer and armature core carried by the arbor, and a spring tending to draw the armature core through the solenoid coil from the wider toward the narrower portion of the armature core.

1. A portable electrical measuring instruarmature carried by the arbor, the base plate for the pointer and i base plate, the spring 966,421 &

having a bearing therein for oneend of the an abutment for the armature core in its 10 arbor, a bearing for the other end of the non-indicating position. arbor struck up from the base plate, a volute In testimony whereof I have afiixed my spring sur'oufilding'thedarbor and connected signature in presence of two Witnesses. at one en t ereto, an an anchor for the v other end of the spring'estruck up from the WALTER BEEDE' ing adapted to op- Witnesses: pose the attractive action of the solenoid WM. ASHLEY KELLY, coil an? the annulus of the ca'singforming VIoToR D. BORST. 

